All prior art disc drives include some means of adjusting the magnetic transducer locations in a radial direction to permit the best possible agreement with standardized data track or ring positions. In the prior art, this adjustment usually requires loosening fastening devices which secure a rotary stepper motor to its supporting structure. Thereafter the stepping motor is rotated until the desired radial position of the transducer is achieved, at which time the fastening devices are secured.
Frequently, the motor to be rotated is too hot to touch, and tools or gloves must be used to effect the rotation. Also, the act of re-securing the fastening device often causes a change in the adjustment, requiring multiple loosen-adjust-tighten sequences before a satisfactory adjustment is achieved. Because of the time and difficulty of performing these multiple adjustment sequences, wider than optimum alignment tolerances are adopted as practical necessities.
A further problem is the excessively fine adjustment required. For example, a 200 step per revolution motor driving a carriage containing the transducer means at a pitch of 96 increments per inch requires an adjustment of .+-.1/58 of an angular degree in order to align the carriage within .+-.100 microinches of the standardized position.
In these systems which are adjustable by rotating the stepper motor, the electrical connections to the motor must necessarily be flexible to permit that rotation. In practice this adds the expense of manufacturing and terminating six to eight flexible conductors.
Most drives have no means of adjusting the transducer locations in a tangential or angular direction. Frequently expensive machining operations are used to achieve an acceptable degree of assembled alignment. One prior art design provides an angular adjustment by loosening two motor support screws, and laterally sliding a motor support before retightening the two screws. This design suffers all of the problems described heretofore in the prior art radial adjustment systems.